1. Field of the Invention
Aspects of the present invention relate to a fuel cell system.
2. Description of the Related Art
Fuel cells have received much attention as one of the next generation, battery-like, energy sources. Fuel cells are high efficiency electricity generation devices and can be used to replace primary cells and/or secondary cells, as power sources for mobile electronic products, such as, mobile phones and notebook computers. Fuel cell systems include one or more fuel cells operated in conjunction with other elements of the fuel cell system. Although the fuel cell is a core component of the fuel cell system, the fuel cell does not operate by itself. The phrase “a fuel cell is mounted on an electronic product” denotes that a fuel cell system is mounted in the electronic product.
FIG. 1 is a schematic diagram showing a configuration of a conventional fuel cell system. Referring to FIG. 1, the conventional fuel cell system includes a cartridge 10, a fuel cell unit 12, a water tank (recycler) 14 that is a vapor/liquid separator, a heat exchanger 16, a heat dissipation fan 18, an air pump 20, a fuel pump 22, a feed pump 24, a circuit unit 26, and an auxiliary power source 28. Methanol, which is a fuel that is supplied to the fuel cell unit 12, is stored in the cartridge 10. Electricity is generated by an electrochemical reaction in the fuel cell unit 12, between the fuel supplied from the cartridge 10, and air (oxygen) supplied by the air pump 20. Water is supplied from the recycler 14 to dilute the fuel. In the electrochemical reaction, carbon dioxide and water are produced.
High temperature steam, generated during operation of the fuel cell unit 12, is cooled in the heat exchanger 16 and stored in the recycler 14, after the vapor and the liquid are separated. When the high temperature steam is cooled in the heat exchanger 16, heat from the steam is transferred to the heat exchanger 16. Heat transferred to the heat exchanger 16 is discharged to the outside by the heat dissipation fan 18. The air pump 20 supplies air (oxygen) to the fuel cell unit 12, during operation of the fuel cell unit 12. The fuel pump 22 supplies fuel from the cartridge 10 to a feed pump 24, when the fuel cell unit 12 starts. The feed pump 24 circulates diluted fuel in the fuel cell system and supplies the diluted fuel to the fuel cell unit 12. The circuit unit 26 controls all elements described above, except for the heat exchanger 16. The auxiliary power source 28 supplies power required for operating the circuit unit 26, the heat dissipation fan 18, the fuel pump 22, the feed pump 24, and the air pump 20, until a sufficient amount of power is output from the fuel cell system.
As described above, the conventional fuel cell system requires a facility for storing a large amount of liquid (water), to dilute the fuel to a low concentration, and also requires a pump besides the heat exchanger 16 or the recycler 14, to reuse water produced during the operation of the fuel cell unit 12. Therefore, the conventional fuel cell system has a large volume.
In the conventional fuel cell system, power must be supplied for the operation of the fuel pump 22, the feed pump 24, and the heat dissipation fan 18. Therefore, these components increase the overall power consumption of the conventional fuel cell system. Also, noise caused by the operation of the various pumps 20, 22, and 24, is considerable.
In the conventional fuel cell system, a relative location of the recycler (water tank) 14 with respect to the fuel cell unit 12, is specified. Therefore, if the location of the recycler 14 with respect to the fuel cell unit 12 is not properly maintained, it is difficult to supply water from the recycler 14 to the fuel cell unit 12.